1. Field of the Invention
The invention relates to crimping an electrical connector onto an electrical conductor and, more particularly, to a crimp die adapted to form a crimp overlap indicia.
2. Brief Description of Prior Developments
Many electrical conductor transmission or distribution splice electrical connectors have substantial overall length in order to help carry very high mechanical and electrical loads. These connectors are often crimped with mechanical or hydraulic crimping tools, and employ the common practice of recommending that crimps ‘overlap’. This overlapping process is important for a number of reasons; namely, that the outside surface of the crimped connection is flat without any sharp edges to prevent corona discharge, and also so that the force per unit area applied to the connection is consistent along the entire length of the crimped connection, resulting in consistent conductor strand loading along the entire length of the connection. Further, many of these connectors are designed with a taper at each end, again to prevent corona discharge, but also so that the transition of mechanical stresses from the un-crimped conductor to the fully crimped conductor inside the barrel of the connector is gradually transitioned. This prevents stress concentrations on individual strands which, when exposed to high tensile loads, may fail prematurely if the stress is not transitioned appropriately.
It is common practice for manufacturers of crimp dies, crimp tools, and electrical connectors to design connector installation tools of various output forces, in order that they may be used in particular markets or used in particular applications. Tools which are designed with ‘low’ output forces, such as about 12-15 tons of output force to the connector, would utilize crimp dies that have a given geometry (such as crimp groove radius, relief angle, and break edge radius) that are common to many types of die platforms, with the exception that the ‘width’ of the die is small to compensate for the relatively low tonnage of the crimping tool. Likewise, a tool which is designed with a ‘high’ output force, such as 60 tons for example, often employ the same crimp groove geometry except that the plow-width is substantially greater, because the tool output is so much greater. Sometimes there is even a direct relationship between output force and plow width. An example may be that a crimp die for a 60 ton tool will have a plow width of 2 inches, and a die with the same crimp groove geometry for a 15 ton tool will have a plow width of 0.5 inch. This 4:1 ratio (as an example) allows different tools to be used on the same connector, resulting in a nearly identical crimp dimension, regardless of the output force of the tool.
Often times, as previously stated, care is given to insure that the user ‘overlap’ crimps by stamping into the given connector the statement ‘OVERLAP CRIMPS’ by the manufacturer of the connector. However, there is no mention given to the amount that these crimps should be overlapped, nor is there a current means to suggest or instruct the user how to consistently overlap these crimps to optimize the force imparted on the connector during the installation process; besides the common practice of ‘eye-balling’ it. Connectors could be pre-marked, but markings are very often obliterated during the crimping process, rendering the pre-marking useless.
There is a need for a system which can provide a user a means for positioning a crimp die on an electrical connector for forming repeatable, consistent overlapping crimps on the electrical connector; thereby optimizing the overlapping crimp process.